Protection for armature windings



April 18, 1933- I A. OLDENBURG 1,904,514

PROTECTION FOR ARMATURE WINDINGS Filed May 1, 1931 Pea-area Apr. '18, 1933 UNITE sig'ra'ras PATENT OFFICE ALFRED OLDENBUBG, nmm-cmw'r'rmune, GM, ASSIGNOB IO BIEKENQ-SGHUOKEBTWEBKE AKTIZNGESELLBOEAIT, O! BERLIN-SIEIENSSTAD'I, exam, A (DBPORA'IIO'N 0! exam! norm-non roe. mama: wnmmes' Application man 1, 19:1, Serial in.

My invention relates to im rovements in electric motors and more particularly an arran ement for the protection of the windmotors.

ingp he ends of the armature coils of the magnetic coil carriers of motors, e ially the coils of the stator winding of in uction motors are often covered with a protecting mass or compound, by which the protruding ends of the coils are completely sealed a inst the outside atmosphere. With this met od, however, the disadvantage often arises that, owing to the heat developed in service, the copper of the coil ends expands more than the compound does, so that particularly at the place where the compound joins the core end plate of the stator cracks occur, by which the protection afforded b the com ound is substantially afiected. his: dis vantage by afiixin an absorbent material to the end surface 0 the packet of stator laminations, which absorbent material forms an elastic intermediate layer at the joint between the compound and the packet of laminations, so that cracks due to the difference of expansion of the copper of the winding and the compound can no moreoccur at the joint, even at the occurrence of ve great difierences of temperature. For t is purpose, a fabric, for exam le of jute or the like, may be employed. Forous plates may also be used. Adhesive substances having a sufiicient adhesive strength for this purpose are known. As various "compounds, e. g. those produced from derivates of cellulose, also possess a great adhesive strength, it is sometimes not necessary to use s ial adhesive substances for a-flixing the said fabrics. By means of the adhesive substances, the fabrics can be made to adhere so strongly to the stator core plate, that they cannot be removed from same without being destroyed. Other elastic intermediate layers may also be used for purposes of that kind, for example. rubber or caoutchouc plates or the like. Th latter materials are particularly suitable for use, if the motors in question are much exposed to dirt but in service do not become 60 hotter than permissible for these matecan, according to my invention, be avoided 584,174, and in Germany Kay 17, 1980.

rials. It is also possible to allix or to press material on all sides round the core end plate serving to hold the thin laminations together, in order to obtain a particularly sure fixing of the'intermediate layers placed bietween the compound and the stator core p ate.

An example for carrying out the invention is illustrated in the accompanying drawing. The ends 11 of the coils of the stator windin no are completely enclosed by a cap of any kin of suita 1e insulating mass 12, the composition of which'is immaterial for the present invention. Between the cap and the core end plate 13 of the laminated stator 14, an intere5 mediate layer 15 consisting of fabric, 0. g. ute or the like, 'is placed, and tightly united with the end sheet 13 by means of a suitable adhesive compound. The layer of fabric 15' should be very absorbent, so that it combines 7o tightly with' the compound ca 12. The cracks often occurring close to t e core end plate 13 with the usual method of applying the compound ca 12, owing to the i erent temperature coe cients, are avoided by the intermediate layers of cloth 15, as the latter retain a certain elasticity at all times, suflicient to follow the movements of the cap.

' To increase the adhering surface, the layers of cloth afiixed to the core end plates of the stator may be given a suitably corrugated form. Hereby a greater elasticity of the said intermediate layer is obtained.

The invention is particularly suitable for protecting the stator winding of three-phase induction motors, but it can also be applied to advantage for the protection of the winding of other motors or also of electrical apparatus, electromagnets or the like.

I claim as my invention:

v 1. In an electric motor in combination with a magnetic armature carrier having a winding protruding at the carrier ends and a cap of suitable insulating material at each carrier end completely surroundin the'protruding winding ends, of a layer 0 elastic material. disposed between each cap and the pertaining carrier end and being joined firmly to the carrier andthe cap for the purpose set forth.

2. In an electric motor in combination with a magnetic armature carrier having a winding protruding at the carrier ends and a cap of suitable insulating material at each carrier end completely surrounding the protruding winding ends, of a layer of absorbent fabric disposed between each cap and the pertaining carrier end and being joined firmly to the carrier and the cap for the purpose set forth.

3. In an electric motor in combination with a magnetic armature carrier having a winding protruding at the carrier ends and a cap of suitable insulating material at each carrier end completely surrounding the protruding winding ends, of an annular layer of elastic material attached to each carrier end and forming-the supporting base forthe pertaining end cap for the purpose set forth.

4. In an electric motor in combination with a magnetic armature carrier having a winding protruding at the carrier ends and a cap of suitable insulating material at each carrier end completely surrounding the protruding winding ends, of a layer of corrugated fabric disposed between each cap and the pertaining carrier end and being joined firmly to the carrier and the cap for the purpose set forth.

In testimony whereof I aflix my signature.

ALFRED OLDENBURG. 

